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Q&A: NSF/ANSI Standard 61

NSF/ANSI Standard 61 - Drinking Water System Components was published in 1988 to establish minimum requirements for the control of potential adverse human health effects from products that contact drinking water.

NSF/ANSI Standard 61 includes criteria for testing and evaluating products to ensure they do not leach contaminants into the water that would be a health concern. These contaminants include those regulated by the United States Environmental Protection Agency (USEPA) and Health Canada, as well as any other non-regulated compounds that may be of concern.

Application - NSF/ANSI Standard 61 requires a disclosure by the manufacturer of all water contact materials in the product and a disclosure by the manufacturer’s material suppliers of all chemical ingredients in the materials.

NSF formulation review - NSF toxicologists perform a formulation review for each water contact material to determine any possible ingredients, contaminants, or reaction by-products that may potentially leach from the material into drinking water. This formulation review then determines the battery of chemical analyses that will be performed on a particular material.

Plant audit and sample collection - NSF then conducts an inspection of the production facility to verify the product formulation and production process and to ensure adequate quality control procedures are in place to prevent the use of unauthorized materials. Product samples are collected during the inspection and sent to NSF laboratories to be tested to the appropriate exposure protocol of NSF/ANSI Standard 61.

Laboratory testing - Devices or materials are evaluated according to the exposure and analysis methods in Annex B of NSF/ANSI Standard 61. Most products undergo a 3-week exposure process where the products are exposed to various formulated waters designed to extract specific types of contaminants. Contaminant concentrations are determined from chemical analyses of the exposure water samples.

Toxicology evaluation - These contaminant concentrations are then evaluated by a toxicologist to the pass/fail criteria in Annex D and E of NSF/ANSI Standard 61. Products that meet the requirements of the standard are then certified and appear in the NSF Listings. If products fail to meet the requirements of the standard, the manufacturer may identify the source of the failure and resubmit a reformulated product for certification.

Certification granted

Follow-up program - Once products are certified and listed by NSF they are inspected and reviewed on an annual basis.

Listed production facilities are then subjected to unannounced annual inspections by NSF auditors to ensure that certified products are made according to the authorized formulations and processes. Products are collected on a routine basis (typically once annually) for retesting.

Occasionally, certified products will fail an annual retest. When this happens, NSF immediately notifies the manufacturer. NSF requires the manufacturer to stop shipment of noncompliant product and to fully investigate the cause of the failure. An NSF field auditor inspects the facility to ensure the manufacturer has taken these steps. If the manufacturer is able to identify and correct the cause of the failure, they may resubmit the product for certification. If the reformulated product meets the requirements of NSF/ANSI Standard 61, the manufacturer may again mark and sell the products as NSF certified.

NSF/ANSI Standard 61 is overseen by the NSF Drinking Water Additives Joint Committee. This committee has a balance of 1/3 public health regulatory members, 1/3 product manufacturer members, and 1/3 product user representatives. Any proposal to revise the standard is typically assigned to a task group composed of joint committee members and external experts. Task group members are assigned by the chairman of the joint committee.

One standing group is the Health Advisory Board. This group consists of toxicologists from USEPA, Health Canada, state and provincial agencies, as well as toxicologists from industry, and private consulting firms. This group is responsible for reviewing and approving all allowable contaminant concentrations that are published in NSF/ANSI Standard 61.

Any revision that is proposed by a task group must receive majority approval from the joint committee. Any negative ballots from the joint committee must be circulated to all committee members and adjudicated, according to the guidelines of the American National Standards Institute (ANSI).

Once a revision is approved by the joint committee, the proposal passes to the NSF Council of Public Health Consultants, which consists of regulatory officials from public health agencies across North America.

Revisions to NSF/ANSI Standard 61 are also circulated for public comment and any concerns addressed through the guidelines of the American National Standards Institute. ANSI gives final approval to each revision of the standard.

Anyone may submit a proposed change to the standard, as well as other issues for discussion by the joint committee, by submitting an issue paper to the chairman of the joint committee. All meetings of the joint committee are open and may be attended by requesting an invitation from the secretary of the joint committee. Contact standards@nsf.org for further information.

Many companies purchase NSF 61 certified products which are then reprocessed in some manner and resold. These processed or fabricated products do not retain their NSF Certification to NSF 61 unless the facility has an official NSF 61 Listing for the processed or fabricated product.

Example: Fabricated Pipe

A fabrication facility may purchase NSF 61 certified ductile iron pipe and fabricate grooved or flanged pipe and resell the product to a contractor or water utility. The product only retains the NSF 61 Certification if the fabrication facility has a NSF 61 listing for the grooved or flanged pipe. The certification denotes that the fabrication facility is inspected annually and has products periodically retested to confirm the fact that it is using NSF 61 certified pipe, that it has controlled sources of materials used for fittings and welding, and also ensure that any additional coating materials or processing aids are not going to add harmful contaminants to drinking water.

Example: Regenerated and reactivated media

Several process media companies now offer to take spent media from a water utility and regenerate or reactivate the media and then resell it to the water utility at a much lower cost than virgin media. How does the utility know that the media it is receiving back is the same media that they originally sent to the regeneration facility? How can the water utility be assured that the regenerated media conforms to NSF 61 and will not add harmful contaminants to drinking water? NSF 61 contains specific requirements for products and facilities that regenerate and reactivate media. Regenerated or reactivated media is not NSF 61 Certified unless the regeneration or reactivation facility has a NSF 61 Listing for the products.

Example: Repackaged process media

The same rule would apply to companies that are simply repackaging process media or other products. Even if a company is repackaging NSF 61 certified activated carbon, the NSF 61 certification is not maintained if it has not been separately certified for the repackaging company. How can a utility be sure that a company is only repackaging NSF 61 media and not substituting or mixing with some lower cost material that is not certified? Contamination control is another concern addressed by third party certification. If the repackaging facility has been separately certified then the water utility can be reassured that the facility is receiving unannounced annual inspections from NSF to verify the sources and certification of the media that is being packaged.

While a reprocessed or fabricated NSF 61 certified product does not retain its certification, it is still beneficial for manufacturers to choose NSF 61 certified materials for their end product. Choosing NSF 61 certified components or materials will save your company time and expenses when undergoing certification for your product.

Stainless steel, compared to typical steel, is a general class of metal alloys that contains lower levels of iron and higher levels of chromium, vanadium, etc. The actual percent of the various elements yield different physical properties.

No. Only products that are certified to NSF/ANSI Standard 61 can be assumed to meet the requirements of NSF/ANSI Standard 61. Certification to NSF/ANSI Standard 61 includes product testing and production location auditing to ensure ongoing compliance with the health based requirements of NSF 61. This includes testing products on an annual basis, by exposing them to different formulated waters (typically at pH 5, pH 8 and pH 10) and testing for regulated metals such as antimony, arsenic, barium, cadmium, chromium (including chromium VI), copper, lead, mercury, selenium, thallium, and nickel, as well as any other inorganic and organic leachate concerns that may derive from cutting oils, lubricants, process aids, welding, machining, and other forming by-products. The certification process also includes annual unannounced inspections of the manufacturing facility to verify that the manufacturer is making the product using the same raw materials, material suppliers and production process as the products that are tested.

Annex C of NSF 61 provides a list of materials that have been extensively tested under certain conditions, which then can reduce the amount of testing that NSF needs to perform when certifying products to NSF 61. For example several grades of stainless steel have been listed under Annex C at specific surface area to volume ratios and at certain temperatures (23°C and 30°C). When product manufacturers use these materials in their products under these conditions, NSF may not have to do as much testing as we would if they were using other materials. However NSF would still need to audit the manufacturing facility to verify that these materials are being used in certified products, and testing would be required if other materials are in the products, or if the stainless steel is being used at higher temperatures such as domestic (60°C) or commercial (82°C) hot water.

Contact NSF staff for assistance. Have details of your target products and preferred suppliers. NSF staff may be able to help you find the NSF 61 Certified products you seek. NSF can also help you by networking with your preferred suppliers and rapidly arranging the appropriate evaluation of products you need to meet bid specifications and drinking water safety requirements.

Most US States and Canadian Provinces have regulations or policies that require public drinking water system components to comply or be certified to NSF Standard 61. In addition most of the plumbing codes across the US also require products to be certified to NSF 61. While enforcement of these requirements varies greatly by region, these requirements have resulted in a growing number of specifications for NSF 61 for stainless steel and other potable water products.